If Shudder Occurs After TCC has Applied

If shudder occurs after the TCC has applied, most of the time there is nothing wrong with the transmission.

The TCC is not likely to slip after the TCC has been applied. Engine problems may go unnoticed under light throttle and load, but they become noticeable after the TCC apply when going up a hill or accelerating. This is due to the mechanical coupling between the engine and the transmission.

Once the TCC is applied, there is no torque converter fluid coupling assistance. Engine or driveline vibrations could be unnoticeable before TCC engagement.

Inspect the following components in order to avoid misdiagnosis of TCC shudder. An inspection will also avoid the unnecessary disassembly of a transmission or the unnecessary replacement of a torque converter.

• Spark plugs

  Inspect for improper gap, cracks, high resistance or a broken insulator.

• Ignition coil

  Look for a white discoloration or bulls eye marks on the coil. This indicates arcing while the engine is misfiring.

• Fuel injector

  There may be an intermittent internal electrical short.

• Engine mounts

  Vibration from loose or weak mounts can be multiplied by TCC engagement.

• Axle joints

  Check for proper installation, wear and/or damage.

Replace the torque converter if any of the following conditions exist:

• External leaks appear in the hub weld area.
• The converter hub is scored or damaged.
• The converter pilot is broken, damaged, or fits poorly into the crankshaft.
• You discover steel particles after flushing the cooler and the cooler lines.
• The pump is damaged, or you discover steel particles in the converter.
• The vehicle has TCC shudder and/or no TCC apply. Replace the torque converter only after all hydraulic and electrical diagnoses have been made. The converter clutch material may be glazed.
• The converter has an imbalance which cannot be corrected. Refer to FLEXPLATE/TORQUE CONVERTER VIBRATION TEST .
• The ATF is contaminated with engine coolant.
• An internal failure occurs in the stator roller clutch.
• Overheating produced heavy debris from clutch material.
• You discover steel particles or clutch lining material in the fluid filter or on the magnet, when no internal parts in the unit are worn or damaged. This condition indicates that lining material came from the converter.

Do not replace the torque converter if you discover any of the following symptoms:

• The fluid has an odor or the fluid is discolored, even though metal or clutch facing particles are not present.
• Transmission failure did not display evidence of damaged or worn internal parts, steel particles or clutch plate lining material in the unit and inside the fluid filter.
• The vehicle has been exposed to high mileage only. An exception may exist where the lining of the torque converter clutch dampener plate has seen excess wear by vehicles operated in heavy and/or constant traffic, such as taxi, delivery, or police use.